Composites of polyhydroxy fatty acids and fibrous materials

ABSTRACT

The present invention relates to the use of a composite material made of a fibrous material and binders in the form of a polymer of hydroxyfatty acids for the preparation of molded parts in the automobile field, in particular, for acoustic attenuation in the areas of the hood, bulkhead (on both sides), tunnel, door, roof, footwell, pumps, A to D pillars and air distribution duct, and as an optionally self-supporting base for interior trims, especially for instrument panel covers, tunnel linings, door trims, seat back linings, A to D pillar linings and spare wheel covers, and as parts with a double function, especially as roof liner, rear shelf, filling piece, trunk mat or undershield.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the use of composite materials made ofpoly(hydroxyfatty acids) as binders and fibrous materials for thepreparation of molded parts in the automobile field.

2. Description of the Related Art

Composite materials such as textile fiber fleeces consist of fibrousmaterials and a binder material. Phenol resins are mainly used as thebinder although their environmental compatibility is doubtful.

U.S. Pat. No. 5,350,627 A describes the use of biodegradable polymers asbinders for impregnating or coating fibrous fabrics. The resultingfabric is biodegradable so that the fiber in the fabric can be easilyreused. The binder polymers described have molecular weights of morethan 30,000, in particular more than 50,000, and include, for example,polymers of lactic acid, glycolic acid, hydroxybutyric acid andhydroxyvaleric acid.

DE 44 16 357 A1 describes a wound cover for medical use consisting of asupport material of vegetable and/or animal fibers and/or fibers ofpolymer materials, and a polymer material which essentially coats and/orreinforces the fibers, the polymer material consisting of apoly(hydroxybutyric acid) which makes up between 1 and 50% by mass,based on the total mass of the wound cover.

SUMMARY OF THE INVENTION

Textile fiber fleeces are a frequently used construction material in theautomobile field and have a broad range of properties. For example,phenol resin bonded textile fleece has long been employed as a materialfor structural and covered parts (alone or as a composite material) inthe automobile industry in the construction of passenger cars andtrucks, due to, inter alia, its good attenuation properties. Being aninexpensive sheet material, this product at first exclusively served forcushioning purposes. More recently, however, this material becameavailable in a number of variants and can be employed in a wide varietyof uses. Molded parts are particularly preferred.

Phenol resin bonded textile fleece is commercially available in bulkdensities of from 50 to 1000 kg/cm³ and in thicknesses of from 5 to 30mm. It may be described as a so-called porous composite consisting ofthree phases (cotton, cured phenol resin, and air)--a constructionmaterial whose profile of properties can be widely modified. Cotton isfibrous, phenol resin is present as discrete particles and also in theform of a flat network, as a kind of matrix.

By a particular selection of the non-woven (fleece) materials, theacoustic properties and the strength of the composite material can beparticularly controlled. Especially preferred materials for thepreparation of the non-woven material are glass-fiber reinforced orglass-mat reinforced fibrous materials, especially binder-containingtextile fleeces, preferably those consisting of a cotton mixed fabric.Such fleeces are given the desired strength by pressing at an elevatedtemperature.

The particular properties and the performance of this last group ofproducts are accounted for by the chemical and morphological structureof cotton and the thermoset character of the cured phenol resins whichare usually employed as the binders for the cotton mixed fabric fleeces.Other factors affecting the properties are the deformability, thefastness to ironing of the cotton, the statistical abundance of bondingpoints, and the laminate and/or sheathing effect of the binder moleculesadhering along the fibers and being condensed in this way.

The cotton will withstand the manufacturing process virtually withoutany change of its characteristic physicochemical properties. It confersspecific quality features to the product, such as sound absorbability,good values of mechanical strength, impact resistance and resistance toshattering in the cold.

Particularly preferred binders for the non-woven materials are selectedfrom phenol-formaldehyde resins, epoxy resins, polyester resins,polyamide resins, polypropylene, polyethylene and/or ethyl/vinyl acetatecopolymers. After curing, phenol resins have the typical properties ofthermoset plastics which are transferred to the finished product. Thetextile fleece is usually prepared dry from reprocessed cotton andpowdery phenol resin. The curing is effected either in a heating flue orin a press via the uncured semifinished product as an intermediate.Selected textile is employed for the parts to be used in the passengercompartment.

Further, wood-fiber fleece materials are known as a wood material whichis prepared by processing cut and chopped offal timber into a pulp usingcompressed steam and heat. This involves the breaking up of somecellulose bonds. Usually, small amounts of synthetic resin binders(e.g., phenol, alkyl, urea resins), flame-retardants, pesticides(against insects and fungal attack) and the like are added to the pulp,which is formed on molding machines into mostly sheet-like fiber boards,and dehydrated.

If such wood-fiber fleece materials are used as insulating materialsagainst cold, heat and sound, as partition walls, table and floorcoverings etc., they are also coated with varnish or with a syntheticresin film.

In the course of the manufacturing process, the wood-fiber material ismolded, densified and compressed. This primarily uses the entangling ofthe fibers and their natural binding force. By adding binders andhydrophobizing agents and by thermal and other after-treatments, thebinding forces can be increased. Thus, the physical and strengthproperties can be adapted to the intended use.

According to DIN 68753, the following kinds of wood-fiber materials aredistinguished:

wood-fiber hardboards having a bulk density of more than 800 kg/m³ ;

medium-hard wood-fiber boards having a bulk density of more than 350kg/m³ and up to 800 kg/m³ ; and

porous wood-fiber fleece materials, also called wood-fiber damp slabs,having a bulk density of from 250 to 350 kg/m³.

From Derwent Abstract 90-168 964 and the corresponding JP-A-0 211 15 03,there are known molded parts consisting of wood fibers and binders aswell as glass-fiber mats in a laminated condition. The molded part isused for interior trim parts for automobiles and electrical switchcupboards. The material is said to have good dimensional stability andimproved strength as well as acoustic absorption properties.

The woody molding composition is prepared by adding 5 to 30% by weightof a phenolic binder for bonding the woody fibers. Glass-fiber mats arealso obtained by impregnating the glass fibers with a phenol resinsolution, followed by drying. The glass-fiber mats are then placed on aporous sheet, and the woody molding composition is sprayed onto the mat.After the woody molding composition has reached the desired thickness,spraying is stopped, and a sheet is applied to obtain a compositematerial. The latter is shaped in a mold with pressure to give a motorvehicle roof liner base material.

Further, a large number of bacteria are known to store large amounts ofpoly(hydroxyfatty acids) intracellularly under appropriate growthconditions in which an excess of a carbon source is present in themedium along with a deficiency of an essential nutrient salt. A surveyis given in A. Steinbuchel, "Polyhydroxyalkanoic acids", in: D. Byrom(ed.), Biomaterials, Macmillan Publishers Ltd., Basingstoke, p. 123-213(1991). These poly(hydroxyfatty acids) are usually linear polyesters of3-hydroxyfatty acids; in a few cases, there are also found 4-hydroxy- or5-hydroxyfatty acid monomers. The properties of the bacterial polymersare critically dependent on the length of the monomer side chain and onthe monomer combinations. Thus, poly(3-hydroxybutyric acid) (PHB) ishard and brittle whereas poly(3-hydroxydecanoic acid) (PHD) haselastomeric properties. The polyesters mostly consist of units ofseveral monomers having different compositions. With some polymers, suchas co-poly(3-hydroxybutyric acid/3-hydroxyvaleric acid) (PHB/HV), themolar composition can be controlled in the microbiological production bythe addition of different carbon sources. With other polymers, such asPHD (consisting of 30 mole percent of 3-hydroxyoctanoate, 50 molepercent of 3-hydroxydecanoate, 10 mole percent of 3-hydroxydodecanoateand other saturated and unsaturated 3-hydroxyfatty acids), thevariability is highly limited in part. However, there are no technicalapplications of these polymers.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

It has been the object of the present invention to employ the mentionedpoly(hydroxyfatty acids), and partially also new ones, for a newapplication in the automobile field in the form of a binder forcomposite materials which exhibits improved biodegradability over thatof phenol resins, can be readily prepared from natural raw materials,and ensures the same or increased mechanical stability of the compositematerial as compared with known materials of the automobile field.

Surprisingly, it has been found that polymers of hydroxyfatty acids aresuitable as binders for composite materials in the automobile field.

Accordingly, in a first embodiment, the present invention relates to theuse of a composite material made of a fibrous material and binders inthe form of a polymer of hydroxyfatty acids for the preparation ofmolded parts in the automobile field, in particular, for acousticattenuation in the areas of the hood, bulkhead (on both sides), tunnel,door, roof, footwell, pumps, A to D pillars and air distribution duct,and as an optionally self-supporting base for interior trims, especiallyfor instrument panel covers, tunnel linings, door trims, seat backlinings, A to D pillar linings and spare wheel covers, and as parts witha double function, especially as roof liner, rear shelf, filling piece,trunk mat or undershield.

By means of the present invention, it is possible to provide novelbiodegradable composite materials for the automobile field.

Due to their specific properties, such as high rigidity, the compositematerials are particularly suitable for the preparation of textile fiberfleeces, especially glass-fiber reinforced or glass-mat reinforcedfibrous materials and cotton fleeces. It is possible to partly orcompletely replace the usually employed phenol resin binders.

The employed binder confers acoustic properties to the compositematerials which result from the porosity of the material and which makethe materials particularly suitable for the automobile field.

Composite materials according to the present invention preferablycontain natural fibers, especially selected from flax, sisal, hemp, woodwool, mechanical wood pulp, wood fibers, coirs, cotton wad, hay, straw,sawdust, wood shavings, pine chips, glumes of grains, seed scraps, oatflakes, cereals, bran, paper strips and cotton scraps, but alsosynthetic fibers, such as polybutylene terephthalates, polyethyleneterephthalates, nylon 6, nylon 66, nylon 12, viscose or rayon as atextile fiber.

The polymers of hydroxyfatty acids which, according to the presentinvention, are employed as binders in composite materials are preferablyderived from saturated or unsaturated 3-hydroxyfatty acids having from 4to 16 carbon atoms in the fatty acid residue. If the chain length of thefatty acid residue is selected too short, for example, through thebiological conditions in the production of the polymers, the polymerwill become too brittle, whereas a long carbon residue results in thestrength of the material being reduced.

In addition to homopolymers of one monomer of hydroxyfatty acids, it ispossible, for example, by selecting the microbiological conditions, toobtain mixtures of poly(hydroxyfatty acids) and thus copolymers or eventerpolymers.

It is particularly preferred that the polymer of hydroxyfatty acidsconsist of poly(3-hydroxybutyric acid) (PHB), poly(3-hydroxybutyricacid/3-hydroxyvaleric acid) copolymer (PHB/HV) in about equimolarproportions, and poly(3-hydroxydecanoic acid), or mixtures thereof.

The kind and quantity of the binders to be used are essentiallydetermined by the intended use of the composite material. Thus, ingeneral, the use of from 5 to 50% by weight, especially from 20 to 40%by weight, based on the composite material, will be appropriate. In casefurther, per se customary binders are to be employed in the compositematerial, it is possible, however, to reduce the amount of the binderaccording to the invention.

The core of the present invention is the particular suitability of thepolymers of hydroxyfatty acids for the preparation of compositematerials in the automobile field. It is particularly preferred to usethe composite materials according to the invention for acousticattenuation in the areas of the hood, bulkhead (on both sides), tunnel,door, roof, footwell and air distribution duct, and optionally as aself-supporting base for interior trims, especially for instrument panelcovers, tunnel linings, door trims, seat back linings and spare wheelcovers, and for parts with a double function, especially as roof liner,rear shelf, filling piece, trunk mat and undershield.

The mentioned composite materials can be obtained by contacting thefibrous material with the binder, followed by pressing to give thecomposite material. The fibrous materials are suitably combined with thebinders, and the composite materials are obtained by pressing at atemperature in the range of room temperature or above the melting rangeof the binder, but below the decomposition range of the binder. A rangeof temperatures of from 120 to 250° C., especially 180 to 250° C., isparticularly preferred according to the present invention, sincecomposite materials used to date in the prior art, especially textilefiber fleeces, are also pressed at such a temperature in the automobilefield.

The microbiological preparation of the polymers of hydroxyfatty acidsusing microorganisms is known per se. For this purpose, it is possibleto employ the microorganisms which are freely commercially available andto propagate them by suitable methods.

One possible method for the preparation of the composite materialsconsists in mixing the fibrous material with an isolated and purifiedpolymer of hydroxyfatty acids, and pressing at an appropriatelycontrolled temperature. A particularly pure, optically appealingcomposite material is thereby obtained which can be used in the visiblearea, optionally without any backing.

Another possibility of preparing the composite materials consists inmixing the fibrous material with dried microorganisms containing apolymer of hydroxyfatty acids or a paste made therefrom. Thus, in thiscase, the microorganism is not freed from the polymers of hydroxyfattyacids, but incorporated in the composite material along with it.

A variant, according to the invention, of the preparation processconsists in growing the microorganisms producing polymers ofhydroxyfatty acids in the presence of the fibrous material of thecomposite materials to be prepared and another carbon source, harvestingthe bacteria along with the fibers, and pressing in a dried or moistcondition, optionally using additional fibrous materials, into compositematerials. Thus, in this embodiment, the fibrous material itself ispartly employed as a nutrient for the microorganisms. With thisprocedure, the release of PHF granules from cells of Alcaligeneseutrophus has been observed in the presence of finely divided cellulosefibers.

Another possibility, according to the invention, of preparing thecomposite materials consists in growing the microorganisms without afurther carbon source, the fibrous material serving as the sole carbonsource.

It is particularly preferred according to the present invention toemploy a PHF-synthetic gene expressing recombinant microorganism.

The present invention will be further illustrated by means of thefollowing Examples:

EXAMPLES Example 1

The ability to prepare poly(3-hydroxydecanoic acid) (PHD) is limited tothe taxonomic group of the pseudomonads. However, since polyesters suchas PHD or the closely related poly(3-hydroxy octanoate) (PHO) have notbeen prepared in larger amounts as yet, a suitable strain for theproduction thereof had first to be found. For this purpose, freelycommercially available strains of the genus Pseudomonas were firsttested for the utilization of inexpensive substrates, such as gluconate,glucose or saccharose (common sugar), both on solid media and in liquidculture (Table 1). For the culture, a defined mineral medium accordingto Schlegel et al. (1961) having the composition as given below wasemployed.

The strains mentioned below in the Table are freely accessible to thepublic since they are maintained with the Deutsche Sammlung vonMikroorganismen und Zellkulturen (DSM) of Braunschweig, Germany. Insteadof the strains mentioned, other deposited strains also lead tocomparable results.

                                      TABLE 1                                     __________________________________________________________________________    Fermentation conditions for the preparation of PHD in different               Pseudomonas species                                                           Organism    Substrate.sup.a)                                                                     Medium.sup.b)                                                                        Duration (h)                                                                         Culture volume (I)                                                                     Dry weight (g/l)                                                                      PHF (%                                                                                PHF                 __________________________________________________________________________                                                              (g/l)               1 P. putida KT2442                                                                        10% gluconate                                                                        30 × MM                                                                        72     7        18.0    2.6     0.4                 2 P. mendocina                                                                            10% gluconate                                                                        2 × NH.sub.4 Cl                                                                93     30       8.5     47.5    4.0                   (DSM 50017)      3 × Mg/Ca/Fe                                                            3 × SL6                                              3 P. citronellolis                                                                        6% gluconate                                                                         2 × NH.sub.4 Cl                                                                75     8        6.9     85.7    5.8                   (DSM 50332)      2 × Mg/Ca/Fe                                                            2 × SL6                                              4 P. citronellolis                                                                        3% g   1.5 × NH.sub.4 Cl                                                              95     30       3.2     73.6    2.3                   (DSM 50332)      2 × Mg/Ca/Fe                                                     luconate                                                                             2 × SL6                                              5 P sp. (DSM 1650)                                                                        4% saccharose                                                                        1 × MM                                                                         48     8        3.0     27.5    0.8                 6 P. putida KT2442                                                                        4% gluconate                                                                         1 × MM                                                                         24     250      3.4     62.1    2.1                 7 P. putida KT2442                                                                        4% gluconate                                                                         1 × MM                                                                         36     250      4.4     72.8    3.2                                    1.5 × NH.sub.4 Cl                                    8 A. eutrophus H16                                                                        4% gluconate                                                                         2 × MM                                                                         43     250      9.4     73.2    6.9                   (DSM 428)                                                                   9 A. eutrophus H16                                                                        2% gluconate                                                                         2 × MM                                                                         58     250      5.6     69.1    3.9                   (DSM 428) 1% valerate                                                       __________________________________________________________________________     .sup.a) The substrates were added in 2% (w/v) portions.                       .sup.b) The amount of the respective substance given in the literature        (Schlegel et al., 1961) is calculated as 1 x. SL, trace element solution      SL6. The abbreviations of the substances relate to the corresponding salt     (see medium). CDM, cellular dry mass.                                    

Mineral medium (Schlegel et al., 1961):

Na₂ HPO₄.12H₂ O=9.00 g

KH₂ PO₄ =1.50 g

NH₄ Cl=1.00 g

MgSO₄.H₂ O=0.20 g

CaCl₂.H₂ O=0.02 g

Fe(III)NH₄ citrate=1.20 g

SL6 (Pfennig, N., 1974)=0.10 ml

H₂ O_(bidest) =ad 1000 ml, pH 6.9

In the experiments, attention was paid to, in particular, the speed ofgrowth and of polymer storage, and to reduced foaming. Consideringadditionally statements made in the literature (Haywood, G. W.,Anderson, A. J., & Dawes, E. A. (1989b), "A survey of the accumulationof novel polyhydroxyalkanoates by bacteria", Biotechnol. Lett. 11,471-476; Huisman, G. W., De Leeuw, O., Eggink, G., & Witholt, B. (1989),"Synthesis of poly-3-hydroxyalkanoates is a common feature offluorescent pseudomonads", Appl. Environ. Microbiol. 55, 1949-1954;Timm, A., & Steinbuchel, A. (1990), "Formation of polyesters consistingof medium-chainlength 3-hydroxyalkanoic acids from gluconate byPseudomonas aeruginosa and other fluorescent pseudomonads", Appl.Environ. 56, 3360-3367), the strains P. putida KT 2442, P.citronellolis, P. mendocina, P. sp. 15a and P. sp. 45C, in particular,were selected as possible microorganisms for the preparation of PHF. Inexperiments conducted in parallel using glucose or gluconate as thecarbon source, it was found that gluconate is usually a better substratefor the synthesis of PHF.

Four of these strains were grown in test fermentations on a 10 l and 30l scale (Table 1). A preparation process using P. putida KT 2442 andgluconate as the carbon source first proved to be favorable since thepolymer content in this strain was very high at an early time in thephase of logarithmic growth already. Since the other strains examinedsynthesized PHF only in a later course of growth, the process using P.putida KT 2442 could be performed with a significantly lower expenditureof time. Although the fermentations stated under 2 and 3 in Table 1 withP. mendocina and P. citronellolis gave higher yields of cellular drymass and more PHF per liter of culture, they required higher amounts ofnutrient salts and gluconate, in addition to the higher expenditure oftime. P. putida KT 2442 could also be grown to higher cell densitiesthan those described under 5 and 6 (Table 1) as shown by fermentation 1(Table 1).

Difficulties in the fermentations with pseudomonads resided in an almostuncontrollable formation of foam when the pH value of the medium movedto the alcaline range of pH values as sodium gluconate was consumed. Itwas possible to reduce the foaming of the culture, which resulted in aconsiderable loss of the cell mass formed by exportation of the biomassoff the bioreactor, by additional titrating with concentrated phosphoricacid, adding high amounts of defoaming agents (polypropylene glycol,neat) and a low number of revolutions of the stirrer. However, thesemeasures involve the risk of damaging the bacteria by too highconcentrations of chemicals. Low numbers of revolutions of the stirrerlead to low oxygen concentrations which slow down or prevent the processof storing PHD.

Example 2

For producing PHD, about 1 kg of lyophilized cells of P. putida KT 2442from cultures No. 6 and 7 (Table 1) was extracted in a Soxhlet extractorwith 7.5 l of chloroform for seven days. The PHF-containing chloroformsolution was concentrated in a rotary evaporator, and the polymer wasisolated by precipitation in a tenfold volume of ethanol according toLageveen, R. G., Huisman, G. W., Preusting, H., Ketelaar, P., Eggink,G., & Witholt, B. (1988), "Formation of polyesters by pseudomonasoleovorans: effect of substrates on formation and composition ofpoly-(R)-3-hydroxyalkanoates and poly-(R)-3-hydroxyalkenoates", Appl.Environ. Microbiol. 54, 2924-2932. About 360 g of purified PHD resulted,corresponding to a recovery of about 55% of the possible value.

The most favorable amount for pressing fiber materials was establishedto be an amount of 3 g since this amount well utilized the capacity ofthe pressing cell, and a pressed part of sufficient thickness resulted.Due to the rubbery consistency of the PHD, it was dissolved inchloroform in order to ensure sufficient distribution of the polymerwithin the fibrous material, and all fibers were uniformly wetted withthis solution.

A volume of 20 ml of chloroform (with sisal, 5 ml, with wood wool andhemp, 10 ml) was sufficient to be completely taken up by 3 g of fibrousmaterial. Therefore, solutions of from 0.5 to 20% (w/v) of PHF (PHB, seeTable 2, PHD, see Table 3, mixtures of PHFs, see Table 4) in chloroformwere prepared, the fibrous material was added, and the solvent wasremoved by evaporation overnight. The PHD wetted fibers were thenpressed under the conditions given in Tables 2 to 5. Thus, 2 to 10% PHDsolutions turned out to be evidently the most suitable concentrationsfor the preparation of composite materials from PHD and cotton scraps,flax or sisal or hemp. Thus, the pressed parts had PHD contents ofbetween 11 and 40%. When cotton wad was used, the polymer exited fromthe cell at low concentrations already, and polymer contents of between6 and 14% appeared to be favorable. The results are summarized in Tables2 to 5.

                                      TABLE 2                                     __________________________________________________________________________    Preparation of pressed specimens from isolated PHB (consisting                of 100 mole percent of polymeric 3-hydroxybutyrate) and various               fibrous materials                                                             Fibrous CHCl.sub.3                                                                        PHB                                                                              solution                                                                          PHB   pressure                                                                          time                                                                             temp. of                                      material (g)                                                                          (ml)                                                                              (g)                                                                              (%) content (%)                                                                         (bar)                                                                             (min)                                                                            cell (° C.)                                                                 remarks                                  __________________________________________________________________________    Cotton scraps                                                                 3       0   0.23                                                                             --  7.1   200 5  180  - w/o solvent                            3       0   0.30                                                                             --  9.1   200 5  180  - w/o solvent                            3       0   0.45                                                                             --  13.1  200 5  180  +/- w/o solvent                          3       0   0.60                                                                             --  16.7  200 5  180  +/- w/o solvent                          3       20* 0.5                                                                              2.5 14.3  200 5  180  aqueous suspension                       3       20* 1.0                                                                              5.0 25.0  200 5  180  aqueous suspension                       3       0   0  --  0     200 5  180  - blank                                  3       20  0.4                                                                              2.0 11.8  200 5  180  ++                                       3       20  1.0                                                                              5.0 25.0  200 5  180  +++                                      3       20  1.5                                                                              7.5 33.3  200 5  180  +++ too much polymer                     3       20  2.0                                                                              10.0                                                                              40.0  200 5  180  +++ too much polymer                     3       20  0.05                                                                             0.25                                                                              1.6   200 5  180  -                                        3       20  0.1                                                                              0.5 3.2   200 5  180  +/-                                      3       20  0.2                                                                              1.0 6.2   200 5  180  +/-                                      3       20  0.3                                                                              1.5 9.1   200 5  180  +                                        Flax                                                                          3       20  0.33                                                                             1.65                                                                              9.9   200 5  180  ++                                       3       20  0.75                                                                             3.75                                                                              20.0  200 5  180  +++                                      Sisal                                                                         3       5   0.33                                                                             6.6 9.9   200 5  180  ++                                       3       5   0.75                                                                             14.0                                                                              20.0  200 5  180  +++                                      Hemp                                                                          3       10  0.33                                                                             3.3 9.9   200 5  180  ++                                       3       10  0.75                                                                             7.5 20.0  200 5  180  +++                                      Wood wool                                                                     3       10  0.33                                                                             3.3 9.9   200 5  180  ++                                       3       10  0.75                                                                             7.5 20.0  200 5  180  +++                                      Cotton wad                                                                    3       20  0.33                                                                             1.65                                                                              9.9   200 5  180  ++                                       3       20  0.75                                                                             3.75                                                                              20.0  200 5  180  +++                                      Hay                                                                           3       5   0.33                                                                             6.6 9.9   200 5  180  ++                                       3       5   0.75                                                                             14.0                                                                              20.0  200 5  180  +++                                      Straw                                                                         3       5   0.33                                                                             6.6 9.9   200 5  180  ++                                       3       5   0.75                                                                             14.0                                                                              20.0  200 5  180  +++                                      Sawdust                                                                       6       20  0.66                                                                             3.3 9.9   200 5  180  ++                                       6       20  1.5                                                                              7.5 20.0  200 5  180  +++                                      Glumes of grains                                                              6       20  0.66                                                                             3.3 9.9   200 5  180  ++                                       6       20  1.5                                                                              7.5 20.0  200 5  180  +++                                      Wood shavings                                                                 6       20  0.66                                                                             3.3 9.9   200 5  180  ++                                       6       20  1.5                                                                              7.5 20.0  200 5  180  +++                                      Pine chips                                                                    6       20  0.66                                                                             3.3 9.9   200 5  180  ++                                       6       20  1.5                                                                              7.5 20.0  200 5  180  +++                                      Seed scraps                                                                   12      10  1.32                                                                             13.2                                                                              9.9   200 5  180  - oil emerges                            Oat flakes                                                                    12      10  1.32                                                                             13.2                                                                              9.9   200 5  180  -                                        Rye                                                                           12      10  1.32                                                                             13.2                                                                              9.9   200 5  180  -                                        Bran                                                                          6       10  0.66                                                                             6.6 9.9   200 5  180  +                                        Paper strips                                                                  6       10  0.66                                                                             6.6 9.9   200 5  180  ++                                       6       10  1.5                                                                              15.0                                                                              20.0  200 5  180  +++                                      __________________________________________________________________________     Evaluation: - unsuitable; + suitable; ++ well suitable; +++ very well         suitable; - combination of fibrous material and poly(hydroxyfatty acid(s)     can be formed into pressed parts with uniform distribution of the two         components and high strength                                                  *solvent: water                                                          

                                      TABLE 3                                     __________________________________________________________________________    Preparation of pressed specimens from isolated PHD (consisting                of 3 mole percent of polymeric 3-hydroxyhexanoate, 20 mole                    percent of polymeric 3-hydroxyoctanoate, 75 mole percent of                   polymeric 3-hydroxydecanoate and 2 mole percent of polymeric                  3-hydroxydodecanoate) and various fibrous materials                           Fibrous CHCl.sub.3                                                                        PHD                                                                              solution                                                                          PHD   pressure                                                                          time                                                                             temp. of                                      material (g)                                                                          (ml)                                                                              (g)                                                                              (%) content (%)                                                                         (bar)                                                                             (min)                                                                            cell (° C.)                                                                 remarks                                  __________________________________________________________________________    Cotton scraps                                                                 1       0   1.0                                                                              --  50.0  200 5  75   - w/o solvent                            3       0   0.5                                                                              --  14.3  200 5  75   - w/o solvent                            3       20  0  0   0     200 5  75   - blank                                  3       20  0.1                                                                              0.5 3.2   200 5  75   - too little polymer                     3       20  0.2                                                                              1.0 6.2   200 5  75   +/- too little polymer                   3       20  0.4                                                                              2.0 11.8  200 5  75   ++                                       3       20  1.0                                                                              5.0 25.0  200 5  75   +++                                      3       20  1.5                                                                              7.5 33.3  200 5  75   +++                                      3       20  2.0                                                                              10.0                                                                              40.0  200 5  75   +++                                      3       20  3.0                                                                              15.0                                                                              50.0  200 5  75   +++ too much polymer                     3       20  4.0                                                                              20.0                                                                              57.1  200 5  75   +++ too much polymer                     Flax                                                                          3       20  0  0   0     200 5  75   - blank                                  3       20  0.1                                                                              0.5 3.2   200 5  75   - too little polymer                     3       20  0.2                                                                              1.0 6.2   200 5  75   +/- too little polymer                   3       20  0.4                                                                              2.0 11.8  200 5  75   ++                                       3       20  1.0                                                                              5.0 25.0  200 5  75   +++                                      3       20  1.5                                                                              7.5 33.3  200 5  75   +++                                      3       20  2.0                                                                              10.0                                                                              40.0  200 5  75   +++                                      3       20  3.0                                                                              15.0                                                                              50.0  200 5  75   +++ too much polymer                     3       20  4.0                                                                              20.0                                                                              57.1  200 5  75   +++ too much polymer                     Sisal                                                                         3       5   0  0   0     200 5  75   - blank                                  3       5   0.1                                                                              2   3.2   200 5  75   -                                        3       5   0.25                                                                             5   7.7   200 5  75   +/-                                      3       5   0.37                                                                             7.5 11.0  200 5  75   +                                        3       5   0.5                                                                              10  14.3  200 5  75   +++                                      3       5   0.75                                                                             15  20.0  200 5  75   +++                                      3       5   1.0                                                                              20  25.0  200 5  75   +++                                      Hemp                                                                          3       10  0  0   0     200 5  75   - blank                                  3       10  0.2                                                                              2   6.2   200 5  75   +/-                                      3       10  0.5                                                                              5   14.3  200 5  75   +++                                      3       10  0.75                                                                             7.5 20.0  200 5  75   +++                                      3       10  1.0                                                                              10  25.0  200 5  75   +++                                      Wood wool                                                                     3       10  0  0   0     200 5  75   - blank                                  3       10  0.2                                                                              2   6.2   200 5  75   -                                        3       10  0.5                                                                              5   14.3  200 5  75   +                                        3       10  0.75                                                                             7.5 20.0  200 5  75   ++                                       3       10  1.0                                                                              10  25.0  200 5  75   +++                                      Cotton wad                                                                    3       20  0  0   0     200 5  75   - blank                                  3       20  0.4                                                                              2   11.8  200 5  75   ++                                       3       20  1.0                                                                              5   25.0  200 5  75   +++                                      3       20  2.0                                                                              10  40.0  200 5  75   +++ too much polymer                     3       20  1.5                                                                              7.5 33.3  200 5  75   +++ too much polymer                     Hay                                                                           3       5   0            200 5  75   - blank                                  3       5   0.37                                                                             7.4 11.0  200 5  75   ++                                       3       5   0.5                                                                              10  14.3  200 5  75   +++                                      Straw                                                                         3       5                200 5  75   - blank                                  3       5   0.37                                                                             7.4 11.0  200 5  75   +                                        3       5   0.5                                                                              10  14.3  200 5  75   +++                                      Sawdust                                                                       3       10  0      0     200 5  75   - blank                                  3       10  0.33                                                                             3.3 9.9   200 5  75   +/-                                      3       10  0.75                                                                             7.5 20.0  200 5  75   +                                        6       20  0.66                                                                             3.3 9.9   200 5  75   +                                        6       20  1.5                                                                              7.5 20.0  200 5  75   ++                                       Wood shavings                                                                 3       10  0      0     200 5  75   - blank                                  3       10  0.33                                                                             3.3 9.9   200 5  75   +/-                                      3       10  0.75                                                                             7.5 20.0  200 5  75   ++                                       6       20  0.65                                                                             3.3 9.9   200 5  75   ++                                       6       20  1.5                                                                              7.5 20.0  200 5  75   ++                                       Pine chips                                                                    3       10  0      0     200 5  75   - blank                                  3       10  0.33                                                                             3.3 9.9   200 5  75   +/-                                      3       10  0.75                                                                             7.5 20.0  200 5  75   +                                        6       20  0.66                                                                             3.3 9.9   200 5  75   ++                                       6       20  1.5                                                                              7.5 20.0  200 5  75   ++                                       Glumes of grains                                                              3       10  0      0     200 5  75   - blank                                  3       10  0.33                                                                             3.3 9.9   200 5  75   +/-                                      3       10  0.75                                                                             7.5 20.0  200 5  75   +                                        6       20  0.66                                                                             3.3 9.9   200 5  75   ++                                       6       20  1.50                                                                             7.5 20.0  200 5  75   ++                                       Seed scraps                                                                   12      5   0      0     200 5  75   - blank                                  12      5   0.33                                                                             6.6 2.7   200 5  75   - oil emerges                            12      5   0.75                                                                             15.0                                                                              5.9   200 5  75   - oil emerges                            12      10  3.00                                                                             30.0                                                                              20.0  200 5  75   +/- oil emerges                          12      10  1.37                                                                             13.7                                                                              10.2  200 5  75   +/- oil emerges                          Oat flakes                                                                    12      10  0      0     200 5  75   - blank                                  12      10  0.33                                                                             3.3 2.7   200 5  75   -                                        12      10  0.75                                                                             7.5 5.9   200 5  75   +/-                                      12      10  1.37                                                                             13.7                                                                              10.2  200 5  75   +/-                                      12      10  3.00                                                                             30.0                                                                              20.0  200 5  75   +                                        Rye                                                                           12      10  0      0     200 5  75   - blank                                  12      10  1.37                                                                             13.7                                                                              10.2  200 5  75   +/-                                      12      10  3.00                                                                             30.0                                                                              20.0  200 5  75   +/-                                      Bran                                                                          6       10  0      0     200 5  75   - blank                                  6       10  0.66                                                                             6.6 9.9   200 5  75   ++                                       6       10  1.50                                                                             15.0                                                                              20.0  200 5  75   +/-                                      Paper Strips                                                                  6       10  0      10    200 5  75   - blank                                  6       10  0.66                                                                             6.6 9.9   200 5  75   +/-                                      6       10  1.50                                                                             15.0                                                                              20.0  200 5  75   ++                                       __________________________________________________________________________

                                      TABLE 4                                     __________________________________________________________________________    Preparation of pressed specimens from polymer mixtures (PHB/HV,               containing 8% of HV) of poly(hydroxyfatty acids) and cotton                   scraps                                                                        The standard of assessment is the same as that of Table 2.                    Fibrous                                                                             CHCl.sub.3                                                                        PHF                                                                              solution                                                                          PHB   pressure                                                                          time                                                                             temp. of                                        material (g)                                                                        (ml)                                                                              (g)                                                                              (%) content (%)                                                                         (bar)                                                                             (min)                                                                            cell (° C.)                                                                 remarks                                    __________________________________________________________________________    3     0   0.23                                                                             --  7.1   200 5  150  +/- w/o solvent                            3     0   0.30                                                                             --  9.1   200 5  150  + w/o solvent                              3     0   0.45                                                                             --  13.0  200 5  150  +++ w/o solvent                            3     0   0.60                                                                             --  16.7  200 5  150  +++ w/o solvent                            3     20  0.4                                                                              2.0 11.8  200 5  150  ++                                         3     20  1.0                                                                              5.0 25.0  200 5  150  +++                                        3     20  1.5                                                                              7.5 33.3  200 5  150  +++                                        3     20  2.0                                                                              10.1                                                                              40.0  200 5  150  +++ too much polymer                       3     20  0.05                                                                             0.25                                                                              1.6   200 5  150  +/-                                        3     20  0.1                                                                              0.5 3.2   200 5  150  +/-                                        3     20  0.2                                                                              1.0 6.2   200 5  150  +                                          3     20  0.3                                                                              1.5 9.1   200 5  150  ++                                         3     20*)                                                                              0.5                                                                              --  14.3  200 5  150  ++ aqueous suspension                      3     20*)                                                                              1.0                                                                              --  25.0  200 5  150  +++ aqueous suspension                     __________________________________________________________________________

                                      TABLE 5                                     __________________________________________________________________________    Preparation of pressed specimens from various polymers and                    cotton scraps and other natural materials                                     The standard of assessment is the same as that of Table 2.                    Fibrous                                                                             CHCl.sub.3                                                                        PHD                                                                              solution                                                                          polymer                                                                             pressure                                                                          time                                                                             temp. of                                        material (g)                                                                        (ml)                                                                              (g)                                                                              (%) content (%)                                                                         (bar)                                                                             (min)                                                                            cell (° C.)                                                                 remarks                                    __________________________________________________________________________    Biopol**                                                                      3     20  0.4                                                                              2   13.3  200 5  150  +                                          3     20  1.0                                                                              5   33.3  200 5  150  +++                                        3     20  1.5                                                                              7.5 50.0  200 5  150  +++ too much polymer                       3     20  2.0                                                                              10  66.7  200 5  150  +++ too much polymer                       Flour                                                                         3     20*)                                                                              0.33                                                                             1.65                                                                              9.9   200 5  100  +/-                                        3     20*)                                                                              0.75                                                                             3.75                                                                              20.0  200 5  100  +/-                                        3     20*)                                                                              0.33                                                                             1.65                                                                              9.9   200 5  180  +                                          3     20*)                                                                              0.75                                                                             3.75                                                                              20.0  200 5  180  ++                                         Coarse meal                                                                   3     20*)                                                                              0.33                                                                             1.65                                                                              9.9   200 5  100  +/-                                        3     20*)                                                                              0.75                                                                             3.75                                                                              20.0  200 5  100  +/-                                        3     20*)                                                                              0.33                                                                             1.65                                                                              9.9   200 5  180  ++                                         3     20*)                                                                              0.75                                                                             3.75                                                                              20.0  200 5  180  +++                                        Starch                                                                        3     20*)                                                                              0.33                                                                             1.65                                                                              9.9   200 5  100  +/-                                        3     20*)                                                                              0.75                                                                             3.75                                                                              20.0  200 5  100  +/-                                        3     20*)                                                                              0.33                                                                             1.65                                                                              9.9   200 5  180  +                                          3     20*)                                                                              0.75                                                                             3.75                                                                              20.0  200 5  180  ++                                         __________________________________________________________________________     **as in Table 4, containing 18% of HV                                    

PHD, PHB/HV with a content of 8 mole percent of 3-hydroxyvaleric acid (3HV) and "Biopol", a natural polymeric material with a content of 18 molepercent of 3 HV, were also taken up in 20 ml of chloroform. This gavesuspensions, since the polymers are sparingly soluble.

Example 3

In order to press bacteria with a significant proportion of PHF in thecellular dry mass directly without isolation of PHF along with thefibrous material, dried cells of P. putida from fermentation 6 (Table 1)with a proportion of 62% of polymer in the cellular dry mass were groundin a mortar to give a powder. This powder was admixed with the fibers asthoroughly as possible in varying amounts, and the mixture was pressed.The resulting pressed parts clearly showed that cohesion was ensured inzones with much cellular material whereas the material was very loose inregions without cellular material.

In order to achieve a better distribution, appropriate amounts ofcellular material were suspended in chloroform, incubated on a rotaryshaker for about 1 hour, and mixed with the fibers. After evaporatingthe chloroform, the mixture was pressed. In this case too, the pressedparts did not show a homogeneous distribution of the cells, so thatsufficient cohesion of the material was not ensured.

In a further experiment, the appropriate amounts of dried cells wereresuspended in water, incubated on a rotary shaker for about 1 hour, andsubsequently mixed with the fibrous material. This mixture was thenlyophilized overnight and subsequently pressed. The resulting pressedparts exhibited a homogeneous distribution of cells and polymer so thatthis method appears to be particularly suitable for the preparation ofcomposite materials. A mixing ratio of 9 to 30% of cells, correspondingto a polymer content of 6 to 24%, appeared favorable for the pressedparts. The results are summarized in Table 6.

                                      TABLE 6                                     __________________________________________________________________________    Preparation of pressed specimens from various fibrous materials               and dried cells containing PHF (fermentation 14; PHB content                  73%, composition: 10 mole percent of 3-hydroxybutyrate).                      The cells were resuspended in the stated volume (ml) of water,                mixed with the fibers and lyophilized.                                        The standard of assessment is the same as that of Table 2.                    Fibrous Cells                                                                            PHB                                                                              proportion                                                                          proportion                                                                          pressure                                                                          time                                                                             temp. of                                     material (g/ml)                                                                       (g)                                                                              (g)                                                                              of cells (%)                                                                        of PHB (%)                                                                          (bar)                                                                             (min)                                                                            cell (° C.)                                                                 remarks                                 __________________________________________________________________________    Cotton                                                                        3       0.15                                                                             0.11                                                                             4.8   3.5   200 10 180  +                                       3       0.23                                                                             0.17                                                                             7.1   5.3   200 10 180  ++                                      3       0.3                                                                              0.22                                                                             9.1   6.7   200 10 180  ++                                      3       0.45                                                                             0.33                                                                             13.2  9.6   200 10 180  +++                                     Flax                                                                          3/20    0.50                                                                             0.36                                                                             14.3  10.4  200 3  180  ++                                      3/20    1.16                                                                             0.85                                                                             27.9  20.4  200 3  180  +++                                     Sisal                                                                         3/5     0.50                                                                             0.36                                                                             14.3  10.4  200 3  180  ++                                      3/5     1.16                                                                             0.85                                                                             27.9  20.4  200 3  180  +++                                     Hemp                                                                          3/10    0.50                                                                             0.36                                                                             14.3  10.4  200 3  180  ++                                      3/10    1.16                                                                             0.85                                                                             27.9  20.4  200 3  180  +++                                     Wood wool                                                                     3/10    0.50                                                                             0.36                                                                             14.3  10.4  200 3  180  ++                                      3/10    1.16                                                                             0.85                                                                             27.9  20.4  200 3  180  +++                                     Cotton wad                                                                    3/10    0.50                                                                             0.36                                                                             14.3  10.4  200 3  180  ++                                      3/10    1.16                                                                             0.85                                                                             27.9  20.4  200 3  180  +++                                     Hay                                                                           3/5     0.50                                                                             0.36                                                                             14.3  10.4  200 3  180  ++                                      3/5     1.16                                                                             0.85                                                                             27.9  20.4  200 3  180  +++                                     Straw                                                                         3/5     0.50                                                                             0.36                                                                             14.3  10.4  200 3  180  ++                                      3/5     1.16                                                                             0.85                                                                             27.9  20.4  200 3  180  +++                                     Sawdust                                                                       6/10    1.00                                                                             0.73                                                                             14.3  10.4  200 3  180  ++                                      6/10    2.32                                                                             1.69                                                                             27.9  20.4  200 3  180  +++                                     Wood shavings                                                                 6/10    1.00                                                                             0.73                                                                             14.3  10.4  200 3  180  ++                                      6/10    2.32                                                                             1.69                                                                             27.9  20.4  200 3  180  +++                                     Pine chips                                                                    6/10    1.00                                                                             0.73                                                                             14.3  10.4  200 3  180  ++                                      6/10    2.32                                                                             1.69                                                                             27.9  20.4  200 3  180  +++                                     Glumes of grains                                                              6/10    1.00                                                                             0.73                                                                             14.3  10.4  200 3  180  ++                                      6/10    2.32                                                                             1.69                                                                             27.9  20.4  200 3  180  +++                                     Seed scraps                                                                   12/5    2.00                                                                             1.46                                                                             14.3  10.4  200 3   75  +/-                                     12/5    4.64                                                                             3.39                                                                             27.9  20.4  200 3   75  +/-                                     Oat flakes                                                                    12/10   2.00                                                                             1.46                                                                             14.3  10.4  200 3   75  +                                       12/10   4.64                                                                             3.39                                                                             27.9  20.4  200 3   75  +                                       Rye                                                                           12/10   2.00                                                                             1.46                                                                             14.3  10.4  200 3   75  +                                       Bran                                                                          6/10    1.00                                                                             0.73                                                                             14.3  10.4  200 3  180  ++                                      6/10    2.32                                                                             1.69                                                                             27.9  20.4  200 3  180  +++                                     Paper strips                                                                  6/10    1.00                                                                             0.73                                                                             14.3  10.4  200 3  180  ++                                      6/10    2.32                                                                             1.69                                                                             27.9  20.4  200 3  180  +++                                     __________________________________________________________________________

Example 4

By analogy with Example 3, pressed parts of fibrous materials and driedcells which had stored PHD (fermentation 6) were prepared. The resultsare summarized in Table 7.

                                      TABLE 7                                     __________________________________________________________________________    Preparation of pressed specimens from various fibrous materials               and dried cells which had stored PHF (fermentation 6; PHD                     content 62% with a composition of 3 mole percent of 3-hydroxy-                hexanoate, 20 mole percent of 3-hydroxyoctanoate, 75 mole                     percent of 3-hydroxydecanoate, and 2 mole percent of 3-                       hydroxydodecanoate).                                                          The standard of assessment is the same as that of Table 2.                    Fibrous Cells                                                                            PHD                                                                              proportion                                                                          proportion                                                                          pressure                                                                          time                                                                             temp. of                                     material (g/ml)                                                                       (g)                                                                              (g)                                                                              of cells (%)                                                                        of PHD (%)                                                                          (bar)                                                                             (min)                                                                            cell (° C.)                                                                 remarks                                 __________________________________________________________________________    Cotton scraps                                                                         dried cells from fermentation 6 were distributed in fibrous                   material                                                              3/20    0.15                                                                             0.09                                                                             4.8   2.9   200 10 75   - no homogeneous                                                              distribution                            3/20    0.23                                                                             0.14                                                                             7.1   4.3   200 10 75   +/- no homogeneous                                                            distribution                            3/20    0.30                                                                             0.19                                                                             9.1   5.7   200 10 75   +/- no homogeneous                                                            distribution                            3/20    0.45                                                                             0.28                                                                             13.0  8.1   200 10 75   - no homogeneous                                                              distribution                            3/20    0.60                                                                             0.37                                                                             16.7  11.3  200 10 75   + no homogeneous                                                              distribution                                    cells from fermentation 6 were resuspended in 10 ml of                        chloroform, mixed with the fibers and                                         pressed after drying                                                  3/20    0.15                                                                             0.09                                                                             4.8   2.9   200 10 75   - no homogeneous                                                              distribution                            3/20    0.23                                                                             0.14                                                                             7.1   4.3   200 10 75   - no homogeneous                                                              distribution                            3/20    0.30                                                                             0.19                                                                             9.1   5.7   200 10 75   - no homogeneous                                                              distribution                            3/20    0.45                                                                             0.28                                                                             13.0  8.1   200 10 75   +/- no homogeneous                                                            distribution                            3/20    0.60                                                                             0.37                                                                             16.7  11.3  200 10 75   + no homogeneous                                                              distribution                                    cells from fermentation 6 were resuspended in 10 ml of water,                 mixed with the fibers and                                                     lyophilized                                                           3/20    0  0  0     0     200 10 75   - blank                                 3/20    0.15                                                                             0.09                                                                             4.8   2.9   200 10 75   -                                       3/20    0.23                                                                             0.14                                                                             7.1   4.3   200 10 75   +/-                                     3/20    0.30                                                                             0.19                                                                             9.1   5.7   200 10 75   +                                       3/20    0.45                                                                             0.28                                                                             13.0  8.1   200 10 75   ++                                      3/20    0.60                                                                             0.37                                                                             16.7  11.3  200 10 75   +++                                     3/20    0.90                                                                             0.56                                                                             23.1  14.3  200 10 75   +++                                     3/20    1.2                                                                              0.74                                                                             28.6  17.6  200 10 75   +++                                     Flax                                                                          3/20    0  0  0     0     200 10 75   - blank                                 3/20    0.15                                                                             0.09                                                                             4.8   2.9   200 10 75   - blank                                 3/20    0.23                                                                             0.14                                                                             7.1   4.3   200 10 75   +/-                                     3/20    0.30                                                                             0.19                                                                             9.1   5.7   200 10 75   +                                       3/20    0.45                                                                             0.28                                                                             13.0  8.1   200 10 75   ++                                      3/20    0.60                                                                             0.37                                                                             16.7  11.3  200 10 75   +++                                     3/20    0.90                                                                             0.56                                                                             23.1  14.3  200 10 75   +++                                     3/20    1.2                                                                              0.74                                                                             28.6  17.6  200 10 75   +++                                     3/20    0.58                                                                             0.36                                                                             16.2  10.0  200 3  75   ++                                      3/20    1.45                                                                             0.90                                                                             32.6  20.2  200 3  75   +++                                     Sisal                                                                         3/5     0.58                                                                             0.36                                                                             16.2  10.0  200 3  75   ++                                      3/5     1.45                                                                             0.90                                                                             32.6  20.2  200 3  75   +++                                     Hemp                                                                          3/10    0.58                                                                             0.36                                                                             16.2  10.0  200 3  75   ++                                      3/10    1.45                                                                             0.90                                                                             32.6  20.2  200 3  75   +++                                     Wood wool                                                                     3/10    0.58                                                                             0.36                                                                             16.2  10.0  200 3  75   +                                       3/10    1.45                                                                             0.90                                                                             32.6  20.2  200 3  75   +++                                     Cotton wad                                                                    3/10    0.58                                                                             0.36                                                                             16.2  10.0  200 3  75   ++                                      3/10    1.45                                                                             0.90                                                                             32.6  20.2  200 3  75   +++                                     Hay                                                                           3/5     0.58                                                                             0.36                                                                             16.2  10.0  200 3  75   +                                       3/5     1.45                                                                             0.90                                                                             32.6  20.2  200 3  75   +++                                     Straw                                                                         3/5     0.58                                                                             0.36                                                                             16.2  10.0  200 3  75   +                                       3/5     1.45                                                                             0.90                                                                             32.6  20.2  200 3  75   +++                                     Sawdust                                                                       6/10    1.16                                                                             0.72                                                                             16.2  10.0  200 3  75   ++                                      6/10    2.90                                                                             1.80                                                                             32.6  20.2  200 3  75   +++                                     Wood shavings                                                                 6/10    1.16                                                                             0.72                                                                             16.2  10.0  200 3  75   ++                                      6/10    2.90                                                                             1.80                                                                             32.6  20.2  200 3  75   +++                                     Pine chips                                                                    6/10    1.16                                                                             0.72                                                                             16.2  10.0  200 3  75   ++                                      6/10    2.90                                                                             1.80                                                                             32.6  20.2  200 3  75   +++                                     Glumes of grains                                                              6/10    1.16                                                                             0.72                                                                             16.2  10.0  200 3  75   ++                                      6/10    2.90                                                                             1.80                                                                             32.6  20.2  200 3  75   +++                                     Seed scraps                                                                   12/5    2.32                                                                             1.44                                                                             16.2  10.0  200 3  75   +                                       12/5    5.80                                                                             3.60                                                                             32.6  20.2  200 3  75   ++                                      Oat flakes                                                                    12/10   2.32                                                                             1.44                                                                             16.2  10.0  200 3  75   +                                       12/10   5.80                                                                             3.60                                                                             32.6  20.2  200 3  75   ++                                      Rye                                                                           12/10   2.32                                                                             1.44                                                                             16.2  10.0  200 3  75   +                                       12/10   5.80                                                                             3.60                                                                             32.6  20.2  200 3  75   ++                                      Bran                                                                          6/10    1.16                                                                             0.72                                                                             16.2  10.0  200 3  75   ++                                      6/10    2.90                                                                             1.80                                                                             32.6  20.2  200 3  75   +++                                     Paper strips                                                                  6/10    1.16                                                                             0.72                                                                             16.2  10.0  200 3  75   ++                                      6/10    2.90                                                                             1.80                                                                             32.6  20.2  200 3  75   +++                                     __________________________________________________________________________

Example 5

By analogy with the procedure of Example 3, the culture broth ofbacteria was directly mixed with the fibrous material, i.e. withoutlyophilization and subsequent resuspension, then lyophilized andsubsequently pressed. Suitable microorganisms can be seen from Table 8.

                  TABLE 8                                                         ______________________________________                                        The standard of assessment is the same as that of Table 2                     Bacterium   Substrate Fiber content                                                                             Assessment                                  ______________________________________                                        --          --        cotton scraps                                                                             -                                           Rh. ruber   glucose   cotton scraps                                                                             +++                                         Rh. ruber   glucose   cotton scraps                                                                             +                                           M. extorquens B65                                                                         methanol  cotton scraps                                                                             +                                           M. extorquens B65                                                                         methanol  cotton scraps                                                                             +/-                                         M. rhodesianum                                                                            methanol  cotton scraps                                                                             +/-                                         A. eutrophus H16                                                                          gluconate cotton scraps                                                                             ++                                          A. eutrophus H16                                                                          gluconate cotton scraps                                                                             ++                                          P. sp. GP4PH1                                                                             gluconate cotton scraps                                                                             +++                                         P. sp. DSM1650                                                                            gluconate cotton scraps                                                                             +++                                         P. putida KT2440                                                                          gluconate cotton scraps                                                                             -                                           P. putida KT2440                                                                          octanoate cotton scraps                                                                             -                                           ______________________________________                                    

When the microorganisms are additionally lysed prior to the mixing byultrasonic treatment, the pressed parts from charges with M. extorquensB65 showed "++".

Example 6

For examining the utilization of cellulosic substrates by bacteriacapable of storing PHF according to Example 5, the bacteria were grownon various cellulosic materials. Various autoclaved fibrous materialswere placed in liquid mineral medium and inoculated with bacteria fromfresh NB agar cultures. From the increasing turbidity of the solution,which could also have been due to bacterial growth, the presence of autilizable substrate in the nutrient broth could be concluded. Theresults are summarized in Table 9.

                                      TABLE 9                                     __________________________________________________________________________    Utilization of cellulosic fibrous materials by different bacteria             according to Example 5.                                                       The standard of assessment is the same as that of Table                       __________________________________________________________________________                   P. fluorescens var. cellulosa                                                                C. fimi                                         Substrate      1d 2d  4d  7d  1d 2d  4d  7d                                   __________________________________________________________________________    1.0% glucose   +++            +++                                             0.1% octanoate -  -   -   -   -  -   +/- +/-                                  Whatman paper  +/-                                                                              ++ a                                                                              +++ A   +  ++ a                                                                              +++ A                                    Whatman paper-YE                                                                             +/-                                                                              +/- +   +++ A                                                                             -  -   -   -                                    Whatman paper + 1.0% glucose                                                                 ++ +++         +++                                             Whatman paper + 0.1% octanoate                                                               -  -   -   -   -  -   +/- +/-                                  cotton wad     -  -   +/- +   +/-                                                                              +   +   +++                                  cotton         -  +/- +   ++  +/-                                                                              +   ++  ++                                   cotton + 1.0% glucose                                                                        +++            ++ +++                                          cotton + 0.1% octanoate                                                                      -  -   -   -   +/-                                                                              +/- +/- +                                    flax           -  +/- ++  +++ A                                                                             +/-                                                                              +/- ++  ++                                   sisal          +  +   +   ++  +  +   ++  ++                                   wood wool      -  -   -   -   +/-                                                                              +   +   +                                    straw          +  +   ++  ++  +/-                                                                              +   ++  +++                                  hay            +/-                                                                              ++  ++  +++ +/-                                                                              +   ++  ++                                   laser print    +  +++ a                                                                             +++ A   +  +++ A                                        paper tissue   +/-                                                                              ++ a                                                                              +++ a                                                                             +++ a                                                                             +  +++ +++ a                                                                             +++ a                                magazine       +/-                                                                              +   ++ a                                                                              +++ a                                                                             +  +   +++ +++ a                                newspaper      +/-                                                                              +   +   ++  +/-                                                                              +/- +   +                                    __________________________________________________________________________                   Rb. ruber      S. marcescens                                   Substrate      1d 2d  4d  7d  1d 2d  4d  7d                                   __________________________________________________________________________    1.0% glucose   ++ +++         +++                                             0.1% octanoate n.d.           n.d.                                            Whatman paper  +/-                                                                              +/- +/- +/- +* ++* +++*                                     Whatman paper-YE                                                                             +  ++  ++* ++* ++*                                                                              +++*                                         Whatman paper + 1.0% glucose                                                                 +  ++  ++* ++* ++*                                                                              +++*                                         Whatman paper + 0.1% octanoate                                                               n.d.           n.d.                                            cotton wad     +/-                                                                              +/- +/- +/- +  ++  +++                                      cotton         +/-                                                                              +/- +/- +/- +  ++  +++                                      cotton + 1.0% glucose                                                                        +/-                                                                              +/- +/- +/- ++*                                                                              +++*                                         cotton + 0.1% octanoate                                                                      n.d.           n.d.                                            flax           -  -   +/- +/- +* ++* ++* ++*                                  sisal          -  -   +/- +/- +* ++* ++* ++*                                  wood wool      -  -   -   -   -  -   -   -                                    straw          n.d.           n.d.                                            hay            n.d.           n.d.                                            laser print    n.d.                                                                             n.d.                                                        paper tissue   n.d.           n.d.                                            magazine       n.d.           n.d.                                            newspaper      n.d.           n.d.                                            __________________________________________________________________________     *Bacteria adhere to the fibrous material; a: first decomposition phenomen     are visible; A: cellulosic substrate is completely dissolved; d: days; YE     yeast extract; n.d.: not determined                                      

The complete decomposition of cellulosic material was only observed withP. fluorescens var. cellulose and Cellulomonas fimi when grown oncertain substrates (Table 9). of the substrates examined, Whatman paper(a special laboratory blotting paper) and laser prints on white paper,in particular, were completely dissolved and degraded by both organismswithin four days. Within one week, P. fluorescens var. cellulosa alsodissolved flax. Further utilizable substrates are magazine paper andrecycling paper tissues whereas no dissolution phenomena were detectablewithin one week with cotton scraps, cotton wad, sisal, wood wool andother substrates (Table 9). However, on the macroscopicallynon-decomposed substrates, growth of the culture could in part bedetected from an increase of turbidity (Table 9). Octanoic acid inhibitsthe growth of both bacteria. C. fimi was unable to grow without yeastextract, and the growth of P. fluorescens var. cellulosa was slowed downwithout yeast extract (Table 9).

The microscopic image showed that P. fluorescens var. cellulosa becameadhered to the cellulose fibers during growth while this was not thecase with C. fimi. Both strains had been purchased as celluloseutilizing reference strains from the Deutsche Sammlung vonMikroorganismen (DSM). C. fimi did not store any PHF on any of thesubstrates tested whereas P. fluorescens var. cellulosa synthesizedextremely low amounts of PHD (about 1% of the cellular dry mass). Thislow content was not sufficient to bond fibers.

With all of the other bacteria examined, which exhibited little growthon the substrates tested, the cellulosic material remained unchangedmacroscopically, the cellular yield was low, and PHFs could not bedetected by gas chromatography (Table 9). Since most of the materialemployed are natural materials (sisal, flax, straw, hay) or have anotherwise heterogeneous composition (cotton scraps, printed paper), theycontain a wide variety of substances in addition to the basic material,cellulose. These are possibly utilized by different bacteria and used asa substrate for growth. In addition, chemical processing steps in thepreparation of the final products possibly result in an increase ordecrease of utilizability. Therefore, whether the cause of the observedcellular growth of some pseudomonads on cotton scraps, Whatman paper orflax through is based on a degradation of cellulose or of impuritieswithin the fibrous material, could only be established by a completedecomposition of the cellulose. Since cellulose consists of crystallineand amorphous components which can be utilized by bacteria differentlywell, the proportion of these regions within the fibers may possibly byresponsible for limited utilizability and limited growth. Treatment ofthe cellulose fibers, for example, with aqueous sodium hydroxide, priorto the use as a substrate should promote utilizability.

If the above described cultures containing fibrous materials were fedwith glucose supplements, there was immediate onset of growth, and thegrowth of the different strains came to an end after about 24 hours.Granules of accumulated polymers were then visible under a microscopewith phase contrast after 24 to 48 hours. With respect to themacroscopic appearance, two forms could clearly be distinguished. Mostof the cultures then contained homogeneous bacterial suspensions inwhich the cells did not adhere to the fibers. In contrast, a few strainsformed both aggregates consisting of cells only and aggregatesconsisting of cells and fibers. These are P. sp. GP4BH1 which can storePHB and PHD (Steinbuchel and Wiese (1992), "A Pseudomonas strainaccumulating polyesters of 3-hydroxybutyric acid and medium-chain-length3-hydroxyalkanoic acids", Appl. Microbiol. Biotechnol. 37, 691-697) andRhodococcus ruber which is able to accumulate PHB/HV. In the case of Rh.ruber, the addition of thiamine or yeast extract as supplements promotedgrowth. The results are summarized in Table 10.

                  TABLE 10                                                        ______________________________________                                        The standard of assessment is the same as that of Table 2                     Bacterium  Substrate Fiber content                                                                           Assessment/remarks                             ______________________________________                                        Rh. ruber  glucose   flax      +++                                            Rh. ruber  glucose   cotton wad                                                                              ++                                             Rh. ruber  glucose   cotton scraps                                                                           ++                                             Rh. ruber  glucose   flax      +++                                            M. extorquens B65                                                                        methanol  flax      +++                                            M. extorquens B65                                                                        methanol  flax      +++                                            M. extorquens B65                                                                        methanol  cotton scraps                                                                           ++                                             M. extorquens B65                                                                        methanol  cotton scraps                                                                           +                                              M. rhodesianum                                                                           methanol  cotton scraps                                                                           +++                                            M. rhodesianum                                                                           methanol  cotton scraps                                                                           +                                              P. sp. GP4BH1                                                                            gluconate flax      +                                              P. sp. GP4BH1                                                                            gluconate cotton scraps                                                                           +++                                            P. putida KT2440                                                                         gluconate cotton scraps                                                                           -                                              P. citronellolis                                                                         gluconate cotton scraps                                                                           -                                              A. eutrophus H16                                                                         gluconate cotton scraps                                                                           +++                                            A. eutrophus H16                                                                         gluconate cotton scraps                                                                           +++                                                                 (t = 48 h)                                               A. eutrophus H16                                                                         gluconate cotton scraps                                                                           +++                                            A. eutrophus H16                                                                         gluconate cotton scraps                                                                           +++                                                                 (t = 48 h)                                               A. eutrophus H16                                                                         gluconate cotton wad                                                                              +++                                            A. eutrophus H16                                                                         gluconate wood wool +++                                            A. eutrophus H16                                                                         gluconate flax      +++                                            A. eutrophus H16                                                                         gluconate sisal     +++                                            ______________________________________                                    

We claim:
 1. A process for the preparation of a composite material madeof a fibrous material and binders in the form of a polymer ofhydroxyfatty acids the monomers of which are derived from saturated orunsaturated 3-hydroxyfatty acids having from 4 to 16 carbon atoms in thefatty acid residue, characterized in that microorganisms producing saidpolymer of hydroxyfatty acids are grown in the presence of fibrousmaterial, wherein said fibrous material serves as a nutrient for themicroorganisms, and another carbon source, the microorganisms areharvested along with the fibers, and pressed in a dried or moistcondition, optionally using additional fibrous materials, into compositematerials.
 2. The process according to claim 1, characterized in thatmicroorganisms producing polymers of hydroxyfatty acids are grown in thepresence of fibrous material without another carbon source, themicroorganisms utilizing part of the fibrous material as a carbonsource, the microorganisms are harvested along with the fibers, andpressed in a dried or moist condition, optionally using additionalfibrous materials, into composite materials.
 3. The process according toclaims 1 or 2, characterized in that a PHF-synthetic gene expressingrecombinant microorganism is used as said microorganism.
 4. The processaccording to claims 1 or 2, characterized in that said polymer ofhydroxyfatty acids is derived from monomers of one or more differenthydroxyfatty acids.
 5. The process according to claim 4, characterizedin that said polymer of hydroxyfatty acids is selected frompoly(3-hydroxybutyric acid) (PHB), poly(3-hydroxybutyricacid/3-hydroxyvaleric acid) copolymer (PHB/HV) andpoly(3-hydroxydecanoic acid), or mixtures thereof.
 6. The processaccording to claims 1 or 2, characterized in that said compositematerial contains from 5 to 50% by weight of said polymer ofhydroxyfatty acids.
 7. The process according to claims 1 or 2,characterized in that said fibrous material is selected from flax,sisal, hemp, wood wool, mechanical wood pulp, wood fibers, coirs,leather, cotton wad, hay, straw, sawdust, wood shavings, pine chips,glumes of grains, seed scraps, oat flakes, cereals, bran, paper strips,cotton scraps, synthetic fibers, such as polybutylene terephthalates,polyethylene terephthalates, nylon 6, nylon 66, nylon 12, viscose andrayon.
 8. A composite material connpsing a fibrous material and bindersin the form of a polymer of hydroxyfatty acids produced according toclaim 1 or 2 for the preparation of molded parts in the automobilefield.
 9. The composite material of claim 8, wherein said molded partsare adapted for use as acoustic attenuation in the areas of anautomobile selected from the group consisting of a hood, a bulkhead (onboth sides), a tunnel, a door, a roof, a footwell, pumps, A to Dpillars, and air distribution duct.
 10. The composite material of claim8, wherein said molded parts are adapted for use as a base for interiortrims of an automobile selected from the group consisting of instrumentpanel covers, tunnel linings, door trims, seat back linings, A to Dpillar linings and spare wheel covers, said base being optionallyself-supporting, or as automobile parts selected from the groupconsisting of roof liners, rear shelves, filling pieces, trunk mats andundershields.
 11. The process according to claim 6, charactenzed in thatsaid composite material contains from 10 to 35% by weight of saidpolymer of hydroxyfatty acids.